Electric zinc-furnace with integral condenser.



J. THOMSGN. ELECTRIC ZINC FURNACE WITH INTEGRAL; CONDENSER.

APPLICATION FILED JAN. 2, 1913.

Patented Dec. 9, 1913 2 SHEETSSHEET J. THOMSON. ELECTRIC ZINC FURNACE WITH INTEGRAL 00 I APPLICATION FILED JAN. 2, 1913. 1,080,865

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Patented Dec. 9, 1913.

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JOHII THOMSON, OF NEW YORK, N. Y.

ELECTRIC ZINC-FURNACE WITH INTEGRAL CONDENSER.

Specification of Letters Patent.

Patented Dec. 9, 1913.

Application filed January 2, 1913. Serial No. 739,794.

To all whom it may concern:

'Be it known that I, JOHN THOMSON, a citizen of the United States, and a resident of the borough of Manhattan of the city of New'York, in the county andState of New York, have invented certain new and useful Improvements in Electric Zinc Furnaces with Integral Condensers, of which the following is a specification, reference being made to the accompanying drawings, forming a part hereof.

This invention relates to the metallurgy of zinc, having for its object the production of zinc fume which is subsequently condensed to liquid metal.

'A description of the particular means for attaining the desired results and such an elucidation ofthe general principles ap licable thereto as will provide a complete disclosure of the invention will be concurrently pointed out in connection with the description of the accompanying drawings, which represent a preferred embodiment of the invention.

Figure 1 is a transverse center secti. of the furnace, as A or A of Fig.2; Fig. 2 is a longitudinal center section, as B or B of Fig. 1, and Fig. 3 is a detached plan View of a terminal.

This furnace isparticularly intended for the reduction of oxid of zinc combined with carbon as the reagent whereby when adequately heated substantially the following representative reaction ensues, namely: ZnO+G=Zn+CU.

If pure ZnO and are used in precisely I correct relative proportions then the anditions, however, do

swer of the above formula is an exact expression of the .result in that all of the charged material would be volatilized as zinc fume and monoxid of carbon, in which case there would be no. residue. Such connot obtain in commer cial practice as more or less inert residual matter will remain, depending upon the purity of the materials employed, and hence the formula becomes as above stated simply representative. The presence of this residual matter is a cause of difficulty in realizing a successful result. The'heat necessary for decom osing the charge is preferably derived by irect conduction of heat fro-m a resistor H formed by a bed of broken carbon interpolated between terminals suitably connected to a' power circuit. The charge material P is fed to the upper surface of the resistor through transverse slots or galleries -5 formed by tiles or slabs 6. It will be observed that the lower edges 7 of the slabs do not quite reach to the surface of the resistor and that they are wide enough so that when the galleries are filled with charge material transverse spaces 8 will be provided. into which the volatilized products of the reaction are free to flow. According to the foregoing system the resistor is virtually divided into alternating cross sectional I zones, one for the-down-fiow therethrough of the fume and gas, and the other for inert residualnratter, and so on throughout the len th'of the bed.

he condenser is chiefly comprised in a .condensing resistor or a filter bed I, as

the'c'ase may be, supported by spaced grate bars 9 resting upon ledges 10 andwhich may also have a central support, as by means of plates 12, perforated as at 13, to ermit a free interchange of fume and gas rom one side to the other. Upon the upper'surface of the resistor filter bed one or more series of spaced cross stacked bars or rods are placed, as a transverse series 14 and a longitudmal series 15' which serve inturn to support the reaction resistor H. Thus the reaction system and the condensing system are both contained in a single chamber, in

other words the filter bed lies directly be neath and serves to sustain, through the intermediary grill of rods, the reaction resistor.

1n the bottom of the condensin chamber is a' bath of molten zinc 16 with a ice chamber as 6 between the bath and the grate bars, whose spaces as 17 are in communication with the said chamber.

Beneath the bottom of the condensing chamber is a sub-divided flue T, T in which fuel heat or cold air may be circulated, as through the tubes 18, 18 for the purpose 0 controlling the temperature of the bath.

Extending along each side of the furnace to the full extent of the height and length of the chamber in which the reaction resistor and the filter bed is contained, are chambers or galleries C, C the bottoms of which are connectedby a series of rightand left hand ports, as 19, 20, to the space e, and from the tops of which are tubes as 21, 22, leading to atmosphere. These galleries are entirely unobstructed except with such, necessary thrust pieces 23 as may be required for ob,- taining stability of the walls. j

The operation is as follows: When the reactionis under way, all of the products thereof must pass down through the bed of carbon resistor, the volatilized products through the several zones provided therefor and the same as to the inert residue. In this wise, if any pernicious oxidizing me dium such as CO is produced at and escapes from the seat or seats of the reaction, a sec- -ondary or cleansing reaction will take place in passing through the incandescent carbon bed, and if the evolution is more rapid at one seat than the other the fume and gas will expand and equalize when the spaces between the-rods are reached, as 24, 25. -The upper surface of the filter bed will have a temperature, by radiation and conduction, approximating that of the lower surface of the reaction resistor, but. from thence down to the grate bars the temperature progressively decreases by conduction of heat to and through the bath to, a point somewhatabove that at which the liquid .metal is maintained. Consequently the socalled filter bed plays theadditional role of presenting a large difi 'using surface and also a considerable mass of material possessslow, hence if any fume has been entrained I by the CO it will again have opportunity to precipitate into the troughs 8 either as fluid or blue powder or both. As these galleries quite blanket the sides of the resistor and the filter their. heat will be largely conserved for useful efit'ect. .The

. pose of regulation, also to-exclude a backmonoxid of carbon in the side galleries also serves to prevent any infiltration of air through the outer furnace walls.

The obstruction to the flow of the fume and gas produced by the friction of the interstitial spaces in the resistor and the filter,

may be partially or wholl nullified by means of natural; or 'artificia draft applied to the tubes which may also be providedwith dampers or valves, -as26, for the purflow of air, as when repairing or suspending the operation of the furnace and to-forcea flow of CO to the small test pipe 27 When a good quality of igneousoxid. and reaction coke is employed the inert residual matter will be of relatively small volume and usually -in the form of a fine ash or granusulating the resistor from the filter.

'lated sinter. Thls material finds its way are formed is preferably of re-crystallized carborundum (SiC) which serves the additional function of somewhat electrically in- Consequently,-it becomes feasible to provide the filter with terminals, as 28, whereby it may be separately utilized as a resistor Several advantages of controlling importance are derived from this. Thus in starting up a furnace the filter bed may be preheated' to a proper temperature before the reactiontakes place. Again, if the rate of evolution of fume and gas is such that the temperature of the filter might fall to the freezing point of zinc, suflicient energy may be sent therethrough to avoid this. Finally, if an excessive accumulation of inert residue takes place either on top of or in the filter, a high input of current may be temporarily injected suflicient to disinfia grate any agglomerated sinter, or by the addition of a suitable flux, to fuse it. 7

As doubtless will have been perceived, the inert residue may pass down to and floats upon the zinc bath which is preferably maintained at about a constant level, and this can be readily accomplished as by means of a siphon 29 or by intermittent tapping as denoted by the tap hole 30. At longer intervals when there is a considerable accumulation of residue the blocks 31, 32, may be removed and the residual matter may be scraped out through the large openings 3.3 34.

lhe reaction resistor and the filter bed may be electrified by separate circuits or they may be in parallel or inv series in the same circuit or the filter bed may be otherwise incited as from ashunt circuit.

In the present case a preferred modeof forming the contact endsof the terminals 8 or 28 is shown in Fig. 3 and-consisting in notches r. In this wayan enlarged surface area is provided and the carbon may settle downwardly Without sensibly affecting the integrity or efliciency of the contacts.

Various modifications may be "made inthe details without departingfrom the essential principles herein shown and described; thus for example, insteadof "causingf-the filter bed to directly support the reaction resistor the la ter may rest upon a distinct grating mount upon ledges, as in the instance of the grate bars 9, and an expanding chamber 9 may be thus readily provided between the upper and lower surfaces of the two carbon beds; or, again, the rod grill may be substituted by pieces of broken carborundum.

providing crosswise of their faces the V What I claim is:

1. In an electric zinc furnace, a bed of caribou reaction resistor supported ona filter" Y 2. In an electric zinc furnace, a bed of carbon reactlon resistor, a carbon filter bed e213 an interposed spaced formed-of. r s.

.3. an electric zinc furnace, a bed ofing, and a carbon resistorsupported on said tion resistor 5. In an electric zinc furnace, a bed of carbon reaction resistor, a carbon filter bed and an interposed spaced grill or grating of lesser electrical conductivity than the overlying and underlying carbon.-

6. In an apparatus comprising an electric zinc furnace and condenser, a system of spaced grate bars, beneath which is a'bath of molten metal and a free chamber, an

overlying carbon filter bed, a separating grill or grating, and a bed of carbon reacfor receiving thereupon a charge of oxid of zinc and carbon, said apparatus beingconstructed so that all of the products of the reaction passing downwardly toward and finally impinging upon the said molten bath. I V

7. In an electric zinc furnace, a bed of carbon reaction resistor, a carbon filter bed and a bath of molten metal, all contained in acommon chamber. v

8. In an electric zinc furnace, a bed of carbon reaction resistor, a carbon filter bed, a' bath'of molten metal, all contained in a common chamber, and blanketin side alleries into and through which t e resi ual volatilizedproducts ofthe reaction are which may be electr caused to flow.

9. In an electric zinc furnace, a chamber containing means for producing thereaction, means for efi'ecting condensation of fume, galleries on opposite sides of the reaction chamber, a'port or ports for connecting thechamber to the galleries, and openings' for conducting the residual volatile product-or products to atmosphere. I

'10. In an electric zinc furnace, a bed of carbon reaction resistor electrically se a-' rated from an undeiilfiying carbon filter 11. In an electric zinc furnace'having a system of spaced grate bars, a carbon filter bed, a superimposed bed of carbon reaction resistor and a system for supplyig the.

charge in distinct layers, 'whereb the said resistor and filter are separated into alter-' nating' transverse zones through which the volatile and the inert products of the reaction are caused to pass in a downward direction sidevby side.

12. In the metallurgy of zinc an electric furnace having in one chamber an electric resistor which is utilized to create heat for the purpose of. causing reaction in the charge, thus producing zinc fumes, and under the resistor a carbonfilter through which the zinc fumes pass downwardly to the underlying zinc bath.

13. In the metallurgy of zinc a furnace having in the reaction chamber thereof a bed of carbon resistor below which is 10- cated a carbon filter over a metal bath, the.

filter and the bath being located in the same chamber as the resistor. 14. The combination in an apparatus'of the class described, a reaction chamberprovided with a resistor for producing zinc fumes when sufiicient electric current flows through the resistor and beneath the resistor a fumecondensing means comprising broken carbon supported on a grate located over a liquid zinc bath. v

15. In an electric zinc furnace a charge of reaction material, a primary reaction resistor and a secondary resistor, the primary resistor being sustained by the secondary re.-

sistor and the zinc fumes passing downwardly from the zone of the reaction through both of said resistors during the process of condensation.

16. In an electric zinc furnace a charge of reacting materials, a primary reaction resistor and a secondary resistor, the primary resistor beingfsustained on the secondary resistor and the volatilized and residual prod nets of the reaction passing downwardly through the zone of the reaction through both the saidresistors during the process of condensing the zinc fumes to liquid metal, the furnace also being provided with abath of liquid zinc over whichthe fumes must pass before the residual fumes leave the condenser.

17. In an apparatus of the class described, a bed resistor located ever a second'resistor of broken carbon,'said resistors being separated by a grill of cross members.

This specification signed and witnessed this 31 day ofDecember A. D. 1912. I

' JOHN THOMSON.

Signed in the presence of- EDWIN A. PACKARD, D. I'IAROLD BUsH. 

